FORD 2013 F-550 v.1 - Manual (Page 305)

What You Should Know About Fail-Safe Cooling (If Equipped)
WARNING: If fail-safe cooling activates, pull off the road as soon
as safely possible and turn the engine off. The engine may
automatically shut off while driving without further indication.
If the engine coolant supply is depleted, this feature allows the vehicle to
be driven temporarily before incremental component damage is incurred.
The “fail-safe” distance depends on ambient temperatures, vehicle load
and terrain.
How Fail-Safe Cooling Works
If the engine begins to overheat:
• The engine coolant temperature gauge will move to the red (hot) area.
• The information display will indicate the engine is overheating.
• The service engine soon indicator will illuminate.
If the engine reaches a preset over-temperature condition, the engine
will automatically switch to alternating cylinder operation. Each disabled
cylinder acts as an air pump and cools the engine.
When this occurs the vehicle will still operate. However:
• The engine power will be limited.
• The air conditioning system will be disabled.
Continued operation will increase the engine temperature and the engine
will completely shut down, causing steering and braking effort to increase.
Once the engine temperature cools, the engine can be restarted. Take
your vehicle to an authorized dealer as soon as possible to minimize
engine damage.
When Fail-Safe Mode is Activated
WARNING: Never remove the coolant reservoir cap while the
engine is running or hot.
Note: Driving the vehicle without repairing the engine problem increases
the chance of engine damage. Take your vehicle to an authorized dealer
as soon as possible.
304 Maintenance
2013 F-250/350/450/550 (f23)
Owners Guide gf, 1st Printing
USA (fus)